the study was funded by the california breast cancer research program, which is based in oakland. laura. >> thank you very much, marla. it's 5:45. >>> some cancer patients call it chemo brain and this morning we're learning more about what causes it. doctors have discovered physical evidence that chemotherapy causes changes in the brain affecting a patient's concentration and memory. after studying more than 100 patients, researchers found that although there was little difference in brain volume, there were significant changes in brain metabolism in areas linked to planning and prioritizing. >>> also concerning your health, grapefruit and certain drugs just don't mix. this can be a very dangerous combination and a lot of doctors may be unaware of the risks. canadian researchers say there are now 85 drugs that may interact with grapefruit and half can have serious side effects or even cause sudden death. grapefruit contains a chemical that can either accelerate the effects of certain drugs or block the absorption of others, even when eaten many hours before taking the medication.